Advancing first-person access to experience through sense of certainty training

First-person access to experience is of eminent importance for psychological research and for various applied domains such as the prevention and treatment of mental and physical illness. It is therefore of major interest to find ways to enhance the accuracy of introspective access to experience. Interventions based, for example, on meditation or adaptive feedback training were able to advance the accuracy of metacognitive access (i.e., a subcomponent of introspective access). However, there is an open debate about possible confounds and especially the transfer of the training effect to other domains. With the current series of studies, we aimed to test an intervention to advance introspective access that (1) was based on a conceptualization of the sense of certainty, (2) comprised a first-person approach addressing cognitive as well as affective and somatic dimensions of experience, and (3) prioritized low training duration and attainment of high experiential depth. We investigated a domain-specific (study A, n = 65) and a domain-general (study B, n = 70) effect of sense of certainty training on metacognitive accuracy and finally tried to replicate the domain-specific effect (study C, n = 41). Altogether, the studies showed mixed results regarding a domain-specific and negative results regarding a domain-general effect of the intervention. Based on our findings, we discuss implications of a first-person approach to training systematic self-enquiry. We offer both a conservative and a liberal interpretation of our results and suggest that this important issue is not put aside prematurely and that the training of access to experience through first-person enquiry is given a fair chance in future research.